Very nice work! I can see that you were working with an ellipse guide, which is kind of surprising considering the size of each wheel. Most students end up getting a "master ellipse template" which has a bunch of different degrees, but limited to a smaller range of sizes. Despite that, it's still adequate for the challenge. I can of course see in some of the earlier wheels that you did have to freehand some of your ellipses, and while they didn't come out as well, this is entirely understandable so I won't get distracted by it.

As a whole, your constructions are really well done. You're really getting the most out of your ellipse guides with all of the concentric ellipses you've included to flesh out each tire, and to capture a lot of their subtle elements - like the slight curvature to the wheel as a whole that helps give it that "inflated" appearance, rather than that of an overly heavy cylinder. You've also done an excellent job of building out each rim and its spokes with a great deal of care. All of this patience contributes immensely to the sense of solidity and believability of each wheel.

When it comes to the tire treads, what you've done here is entirely fine - but I can see that you relied quite a bit on more explicit markmaking than implicit. If you recall, that's something that was discussed back in lesson 2's texture section, talking about how we can either capture the presence of forms by drawing them explicitly - outlining them, building them out using constructional methods, etc. - or we can capture them implicitly, which focuses on the use of cast shadow and the distinct absence of actual outlines.

When it comes to shallower tire treads, this isn't too big of a deal, except for the fact that it does force you to draw every bit of the tread pattern without exception. It doesn't let you rely on the viewer's own brain to fill in the blanks, in the way that working implicitly would. While on one hand this means that you were indeed forced to draw a lot more than was strictly necessary to convey these textures, it also means that you were not in a position to control the density of those textures. When a wheel is floating on its own, that's fine - but if it were part of a larger vehicle, you'd end up with really significant focal points on all of the wheels, simply because of the high contrast textures stealing the focus away from everything else.

Now, if you'd played with any tire treads that had particularly larger, chunkier tread patterns - with large forms jutting out of the tire's surface - then you'd run into cases where those two problems would be a lot more noticeable.

All of this circles back to one simple point - when drawing any kind of texture, always focus your markmaking on defining the specific shadow shapes cast by your textural forms. Don't outline them, as the temptation often is to do. Instead, for each individual textural form, try to hold your understanding of it in space, and how it relates to its surrounding surfaces, in your mind, and based on that, design a specific cast shadow shape. This approach, though obviously quite challenging, will provide you with far greater control over the end result, and will help you improve your ability to get away with less overall labour (even if that work demands more from your spatial reasoning skills, to get the shadows right).

One example I sometimes provide on this topic isn't actually a tire tread, but I feel it applies just as well. Take a look at this bush viper texture, and how the different lighting scenarios we assert for it can allow us to control its density.

Anyway! All in all, your work is still coming along great, and to be honest, the matter of texture coming up here is an intentional trap to remind those who've forgotten about the matters discussed in lesson 2 to review it before finishing up the course. So, you're one of many who've stumbled into this issue.

I'll go ahead and mark this lesson as complete!